I've had some HVAC people here to look at the ticking noise coming from our furnace duct. One of them installed a brace on the piece in question. This seemed to make the ticking less frequent, although the ticking still occurred. Another removed it and loosened the ductwork braces from the ceiling saying the furnace ducts need to "breathe", but this seemed to make things worse.

Any recommendations on getting the noise to permanently stop when running on auto heat?

Please see the video here on YouTube to see what I'm talking about.